Simple Pump Selective for Neon

In Nanosystems, Dr. Drexler proposed and analyzed a variety of molecular machines, including some too large to be specified and analyzed in atomic detail. One such machine was a sorting rotor based upon modulated receptors designed to bind and transport chemical species from a feedstock solution.

One of Dr. Drexler’s more recent projects has been to design in atomic detail a simpler pump intended to provide some of the functionality of the larger and more complex sorting rotors.

Designs for molecular machine parts, produced by K. Eric Drexler, or by K. Eric Drexler and Ralph C. Merkle, that appear on the Web sites of the Foresight Institute and the Institute for Molecular Manufacturing (IMM) are copyrighted by IMM. It is not necessary to obtain permission to use IMM-copyrighted images for either commercial or non-commercial purposes. Permission to use the images is granted on the condition that credit is given and our copyright notice appears in the publication. Images should also contain the URL for IMM (www.imm.org).

Dr. Drexler provides the following brief description of this pump.

The upper image shows the chamber wall to the left, followed by a tube containing the pump housing; to the right (in this exploded view) is the pump rotor.

The lower image is a close-up view of the rotor, showing a grooved cylindrical bearing surface at each end, supporting a screw-threaded cylindrical segment in the middle. The deep grooves separating the bearing cylinders from the middle segment are partly illusory–realistic atomic radii would show these grooves as filled with what usually passes for solid matter. By the same token, the effective shape of the structure has a smoother surface, and ridges formed by lines of atoms on the surface are less knobby.

In operation, rotation of the shaft moves a helical groove past longitudinal grooves inside the pump housing. Only where facing grooves cross is there room for even a small gas molecule, and these crossing points move from one side to the other as the shaft turns. It is hoped that simulation will show this to be an effective pump, with substantial selectivity for different chemical species; the design target was an effective, selective pump for neon.

–K. Eric Drexler

Atomic Coordinates Available

Dr. Drexler has made the pdb file for this pump available at this site using the link below. If you do not have your browser configured with a helper application that can read pdb files, you will see this file as a long text file listing the three dimensional coordinates and connectivities of 6165 atoms. If you do have your browser configured with an application that can read pdb files, or save the file to disk and open it with such an application, then you will see a graphic representation of the intact pump, but one which you can manipulate to inspect from various angles.